package com.itheima.filter;

import com.alibaba.fastjson.JSONObject;
import com.itheima.pojo.Result;
import com.itheima.utils.JwtUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.StringUtils;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


//@WebFilter(urlPatterns = "/*")
@Slf4j
public class LoginCheckFilter implements Filter {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        // 1、获取请求的url地址
        String url = request.getRequestURI().toString();
        log.info("请求的url：{}", url);

        //2、判断请求的url中是否包含login，如果包含，说明是登录操作，放行
        if (url.contains("login")) {
            log.info("登录操作可以放行. . .");
            filterChain.doFilter(request, response);
            return;
        }

        //3、获取请求头中的令牌(token)
        String jwt = request.getHeader("token");

        // 4、判断令牌是否存在，如果不存在，返回错误结果
        if (!StringUtils.hasLength(jwt)){
            log.info("请求头token为空. . .");
            Result error = Result.error("NOT_LOGIN");
            // 手动转换对象(Json)，因为对象在过滤而不是在Controller
            String notLogin = JSONObject.toJSONString(error);
            response.getWriter().write(notLogin);
            return;
        }

        //5、解析token，如果解析失败，返回错误结果(未登录)
        try {
            JwtUtils.parseJwt(jwt);
        } catch (Exception e) {
            e.printStackTrace();
            log.info("解析令牌失败，返回未登录错误信息. . .");
            Result error = Result.error("NOT_LOGIN");
            String notLogin = JSONObject.toJSONString(error);
            response.getWriter().write(notLogin);
            return;
        }

        // 放行
        log.info("令牌合法，放行. . .");
        filterChain.doFilter(request, response);

    }
}
